Copper deficiencies and excessesSUSAN SCHOENIAN AND JEFF SEMLERUNIVERSITY OF MARYLAND EXTENSION

Copper (Cu)Why we think it’s an important topic.

• Sheep are very susceptible to copper toxicity.

• Sheep and goats differ significantly in their copper requirements and tolerance for excess copper in their diet.

• Raising sheep and goats together presents some challenges from the standpoint of copper nutrition.

Copper (Cu)Why we think it’s an important topic.

• “Copper” is being recommended (again) as an anthelmintic.

• Some books and people are recommending that copper be added to sheep diets.

• Copper nutrition is complex because of its interaction with other minerals.

Importance of copper (Cu)Copper is a trace mineral that is a dietary essential.

Hemoglobin formationInvolvement in enzyme systemsNerve functionCardiovascular integrityBone structureConnective tissue formationFertility and reproductionImmune functionProtection against superoxide radicalsPigmentation and hair texture

Copper basics: plants• Fresh grasses are poor sources of

copper.• Acidic soils increase Cu and lower

Mo in forages.• Mo is higher in alkaline or high

organic matter soils.• Copper absorption in plants is

limited by alkaline pH or higher organic matter.

• Liming can increase Mo in forage and disturb the Cu:Mo ratio (Cu:Mo ratios of at least are considered safe and will avoid copper deficiency).

• Copper-containing fertilizer can increase copper levels in plants (e.g. poultry/pig manure).

Soil ingestion can increase intake of copper.

Copper status of forages

Copper basics: animal• Copper is absorbed from the small

intestines.

• Absorbed copper in excess of requirements in stored in the liver (a small amount is removed by the kidneys).

• When net copper absorption is insufficient to meet metabolic requirements, liver stores are mobilized.

• If the concentration of copper in the liver exceeds a certain critical value, there may be a sudden release of massive amounts of copper into the bloodstream, with potentially deadly consequences.

Copper absorption

• More important than its concentration in feed.

• Affected by species, breed, genetics, and age.

• Young ruminants absorb Cu more efficiently.• 70-75% (up to 90%) absorption

in young ruminant vs. > 10% in mature ruminants.

• Copper crosses placenta, but only a small amount is secreted in the milk.

• Ionophores increase efficiency of copper absorption.

Copper absorption is affected by other minerals in the diet

• Molybdenum (Mo) and sulfur (S) form insoluble complexes with Cu and prevent its absorption.• Cu absorption is

decreased when there is excess zinc (Zn) and iron (Fe) in the diet.• Cu absorption can also

be affected by cadmium and vitamin C.

Copper requirementsSHEEP

Cu requirement Reference

5 mg/kg NRC, 1975

1 - 8.6 mg/kg ARC, 1980

7-11 mg/kg NRC, 1985

4.3 – 28.4 mg/kg 1999

Equations which use different absorption coefficients of copper and variable levels of absorption antagonists and metabolic

interactions are used to calculate the copper requirements for different classes

of sheep (NRC, 2007).

GOATSCu requirement Reference

8-10 mg/kg 1991, 2000

10-23 mg/kg 1992

10-23 mg/kg 1997

15 mg/kg*lactating goat

NRC, 2007*Adjustments should be made for the level of Mo and S in the diet.

20 mg/kg*mature goats and bucks

25 mg/kg*growing goats

Maximum tolerable level: 15 mg/kg when diets contain normal Mo (1-2 mg/kg and S (0.15-0.25 percent).

A maximum tolerable level has not been established for goats. Cattle level is 40 mg/kg.

Copper excesses and deficiencies

SHEEP• More likely to

experience copper toxicity.• Sheep are the species

most susceptible to copper toxicity.• There is a narrow

margin between requirements and toxic levels.

GOATS• More likely to

experience copper deficiency.• Goats have a higher

requirement and tolerance for excess copper as compared to sheep.

+

(-)

Two forms of copper toxicity

ACUTE• Caused by ingestion of

high copper feeds, salts, pesticides, poultry litter, or other high copper substances.• Can occur at intakes of

20-100 mg/kg (or ppm).

CHRONIC• High levels of copper are

ingested over time, but at levels below the acutely toxic level.• Usually occurs when

there is a high Cu:Mo ratio.• Stress is usually

the trigger.

Two phases of copper toxicity

PRE-HAEMOLYTIC

• When copper accumulates in liver to exceed 1000 mg Cu/kg DM• Lasts from weeks to

more than a year.

HAEMOLYTIC

• When copper is released from the liver and blood copper values rise.• Lasts from hours

to days.

STRESS

Diagnosis of copper toxicity

1. Clinical signs2. Laboratory tests3. Necropsy4. Determine mineral

concentrations of the diet and other potential sources of excess copper.

Texel sheep are more susceptible to Cu toxicity.

Diagnosis of copper toxicity

Clinical signs• Weakness• Panting• Dullness• Pale mucous membranes• Yellow discoloration

(jaundice) of mucous membranes• Dark brown or red-

colored urine• Abortion• Death

Images from Colorado State University

Diagnosis of copper toxicity

Laboratory tests

• Liver copper• Kidney copper • Blood level• Serum• Plasma

• Liver enzymes

Diagnosis of copper toxicity

Necropsy

Icterus (jaundice) “gun, metal, blue” kidneys

Images from Colorado State University

Diagnosis of copper toxicityDetermine mineral concentrations in diet

1. Copper2. Molybdenum3. Sulfur 4. Iron

Common sources of excess copper

• Errors in feed formulation and mixing

• Consumption of feedstuffs formulated for other animals.

• Consumption of non-traditional feedstuffs that are high in copper.

• Grazing on pastures fertilized with pig or poultry manure.

• Grazing forages deficient in molybdenum.

• Use of copper-containing anthelmintics.

• Use of copper-containing footbaths.

• Copper supplements.

Treatment of Cu toxicity• Usually unrewarding for

severely-affected animals.• Administer both

molybdenum and sulfate as a drench or add to feed.• Ammonium molybdate• Sodium sulfate

• Reduce or eliminate extraneous sources of copper.

Copper deficiencyCommon causes

1. Primary• Low intake of copper

• Fresh forages have less Cu than cured hays.

• Grasses has less Cu than legumes

• Liming reduces Cu uptake by plants.

2. Secondary• High concentrations of

Mo, S, Fe, Cn, Se, and ascorbic acid (vitamin C).

• Alkaline soils

Diagnosis of copper deficiency

1. Clinical signs2. Lab tests3. Necropsy4. Determine mineral

concentrations of the diet.

5. Clinical response to copper supplementation.

Diagnosis of copper deficiencyClinical signs• Anemia• Reduced growth rate• Connective tissue disorders• Generalized osteoporosis• Increased susceptibility to

all diseases.• Neonatal or congenital

ataxia (swayback)• De-pigmentation of skin,

hair, or wool.• Loss of crimp, steely or

stringy wool

Treatment of copper deficiency

• Injectable copper(can cause tissue damage)

• Oral copper(short-acting)

• Copper oxide particles• Mineral supplement• Copper-containing

fertilizers.

Copper as an anthelmintic

1. Copper mineral supplement

2. Copper sulfate(Cu2SO4)

3. Copper oxide wire particles (COWP).

Copper sulfate (Cu2SO4)

• Historical dewormer used in the early 1900’s before synthetic dewormers became available.

• Was often combined with lead arsenic or nicotine sulfate to broaden its efficacy.

• Due to the widespread development of drug-resistant worms, copper sulfate is being re-evaluated as a dewormer.

Copper sulfate (Cu2SO4)

• Usually administered as a 1-1.5 percent solution in water.

• How copper sulfate compares to a synthetic dewormer depends upon the degree of resistance to the synthetic dewormer.

• Recent research has shown that copper sulfate can be effective at reducing fecal egg counts without causing copper toxicity.• When/if used, copper sulfate should

only be administered to clinically-parasitized animals.

• Copper toxicity is always risk if copper sulfate is not administered properly, especially to sheep!

Copper oxide

• Slow dissolving form of copper.

• Not absorbed as well as copper sulfate.

• Sold as a supplement to treat or prevent copper deficiency in cattle.

• Cattle doses need to be re-sized for sheep and goats.

Copper oxide wire particles• Recent research has

shown COWPs to be as effective as most anthelmintics in reducing fecal egg counts.

• However, COWPs are only effective against the barber pole worm.

• COWPs seem to be more effective on young stock.

• Their exact mode of action is not known.

Copper oxide wire particles

• Experts disagree as to whether to recommend COWPs as an anthelmintic for sheep.• Most research has been

done with hair sheep and goats.

• There hasn’t been any copper toxicity in research studies.

Copper oxide wire particles (COWPs)

Recommendations• No problem using COWPs in

goats.• Do not use in sheep unless you

have total anthelmintic failure or you are a certified organic producer.• Check with inspector to see if

COWPs would be allowed as a dewormer.

• Only administer COWPs to clinically-parasitized animals (FAMACHA© 3-5).

• Since copper accumulates in the liver over time, limit the use of COWPs to lambs that will be going to slaughter.

Raising sheep and goats togetherCopper presents a dilemma.

• Feeding sheep mineral (low copper) to sheep and goats increases the risk of copper deficiency in goats.

• Feeding goat mineral (higher copper) to sheep and goats increases the risk of copper toxicity in sheep.

Raising sheep and goats togetherCopper poses a problem.

• Feed them separately.• House them

separately at night• Put mineral feeder

for goats where sheep can’t get it.• Give goats copper

supplements, e.g. boluses.

Questions? Thank you for your attention.